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SubjectRe: [PATCH v4 3/7] drm: rcar-du: lvds: Get dual link configuration from DT
Hi Fabrizio,

Thank you for the patch.

On Fri, Dec 06, 2019 at 04:32:50PM +0000, Fabrizio Castro wrote:
> For dual-LVDS configurations, it is now possible to mark the
> DT port nodes for the sink with boolean properties (like
> dual-lvds-even-pixels and dual-lvds-odd-pixels) to let drivers
> know the encoders need to be configured in dual-LVDS mode.
>
> Rework the implementation of rcar_lvds_parse_dt_companion
> to make use of the DT markers while keeping backward
> compatibility.
>
> Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
>
> ---
> v3->v4:
> * New patch extracted from patch:
> "drm: rcar-du: lvds: Add dual-LVDS panels support"
> ---
> drivers/gpu/drm/rcar-du/rcar_lvds.c | 56 +++++++++++++++++++++++++++++++------
> 1 file changed, 47 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> index 3cb0a83..6c1f171 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
> @@ -669,8 +669,10 @@ EXPORT_SYMBOL_GPL(rcar_lvds_dual_link);
> static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
> {
> const struct of_device_id *match;
> - struct device_node *companion;
> + struct device_node *companion, *p0, *p1;

Could you rename p0 and p1 to port0 and port1, and spit them to a
separate line of variable declaration ?

> + struct rcar_lvds *companion_lvds;
> struct device *dev = lvds->dev;
> + int dual_link;
> int ret = 0;
>
> /* Locate the companion LVDS encoder for dual-link operation, if any. */
> @@ -689,13 +691,55 @@ static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
> goto done;
> }
>
> + /*
> + * We need to work out if the sink is expecting us to function in
> + * dual-link mode. We do this by looking at the DT port nodes we are
> + * connected to, if they are marked as expecting even pixels and
> + * odd pixels than we need to enable vertical stripe output.
> + */
> + p0 = of_graph_get_port_by_id(dev->of_node, 1);
> + p1 = of_graph_get_port_by_id(companion, 1);
> + dual_link = drm_of_lvds_get_dual_link_pixel_order(p0, p1);
> + of_node_put(p0);
> + of_node_put(p1);
> + if (dual_link >= DRM_LVDS_DUAL_LINK_EVEN_ODD_PIXELS) {
> + lvds->dual_link = true;
> + } else if (lvds->next_bridge && lvds->next_bridge->timings) {
> + /*
> + * Early dual-link bridge specific implementations populate the
> + * timings field of drm_bridge, read the dual_link flag off the
> + * bridge directly for backward compatibility.
> + */
> + lvds->dual_link = lvds->next_bridge->timings->dual_link;
> + }
> +
> + if (!lvds->dual_link) {
> + dev_dbg(dev, "Single-link configuration detected\n");
> + goto done;
> + }
> +
> lvds->companion = of_drm_find_bridge(companion);
> if (!lvds->companion) {
> ret = -EPROBE_DEFER;
> goto done;
> }
>
> - dev_dbg(dev, "Found companion encoder %pOF\n", companion);
> + dev_dbg(dev,
> + "Dual-link configuration detected (companion encoder %pOF)\n",
> + companion);
> +
> + companion_lvds = bridge_to_rcar_lvds(lvds->companion);

Could you move this line after the FIXME comment ?

With these small issues fixed,

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> +
> + /*
> + * FIXME: We should not be messing with the companion encoder private
> + * data from the primary encoder, we should rather let the companion
> + * encoder work things out on its own. However, the companion encoder
> + * doesn't hold a reference to the primary encoder, and
> + * drm_of_lvds_get_dual_link_pixel_order needs to be given references
> + * to the output ports of both encoders, therefore leave it like this
> + * for the time being.
> + */
> + companion_lvds->dual_link = true;
>
> done:
> of_node_put(companion);
> @@ -739,13 +783,7 @@ static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
> if (ret)
> goto done;
>
> - if ((lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK) &&
> - lvds->next_bridge)
> - lvds->dual_link = lvds->next_bridge->timings
> - ? lvds->next_bridge->timings->dual_link
> - : false;
> -
> - if (lvds->dual_link)
> + if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK)
> ret = rcar_lvds_parse_dt_companion(lvds);
>
> done:

--
Regards,

Laurent Pinchart

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